EP0470115A1 - Dispositif de direction assistee avec un moteur electrique - Google Patents

Dispositif de direction assistee avec un moteur electrique

Info

Publication number
EP0470115A1
EP0470115A1 EP19900906206 EP90906206A EP0470115A1 EP 0470115 A1 EP0470115 A1 EP 0470115A1 EP 19900906206 EP19900906206 EP 19900906206 EP 90906206 A EP90906206 A EP 90906206A EP 0470115 A1 EP0470115 A1 EP 0470115A1
Authority
EP
European Patent Office
Prior art keywords
steering
steering device
outputs
inputs
sensor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19900906206
Other languages
German (de)
English (en)
Inventor
Armin Lang
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ZF Friedrichshafen AG
Original Assignee
ZF Friedrichshafen AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ZF Friedrichshafen AG filed Critical ZF Friedrichshafen AG
Publication of EP0470115A1 publication Critical patent/EP0470115A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
    • B62D5/046—Controlling the motor
    • B62D5/0463—Controlling the motor calculating assisting torque from the motor based on driver input

Definitions

  • the invention relates to a power steering device according to the preamble of the first claim. It is mainly used for steering motor vehicles.
  • Such a power steering device with an electronic control is known from DE-A 34 29 233.
  • An analog comparator determines the polarity of a steering torque signal with respect to the zero level and outputs a binary signal.
  • the steering torque signal is simultaneously fed to an absolute value circuit, the output signal of which gives the magnitude of the steering torque.
  • the steering torque signal is compared with a normal torque signal and shaped according to a desired characteristic, according to which the current of the electric motor is controlled by pulse width modulation.
  • the direction of rotation of the electric motor is determined by means of a logic circuit by the output signal of the analog comparison.
  • Supply voltages are operated that have a positive and negative potential in relation to the ground potential of the vehicle. Since the vehicle ground is usually connected to the negative pole of the battery, a special voltage converter is required to generate a negative voltage.
  • the invention has for its object to make a power steering device with an electrical control of the type described simple and safe.
  • the construction of the entire control system is very simple due to the small number of components. Furthermore, the reliability is increased due to the simplicity of the circuit and the few components. At the same time, the disadvantage of the known control system is avoided that the signal levels in the control system shift inadmissibly if one of the symmetrical supply voltages fails. In addition, the zero point stability is improved since parameter shifts due to temperature fluctuations or material aging etc. have the same effect in both signal paths.
  • a steering signal is usually, for. B. in power-assisted steering devices, a signal proportional to the steering torque (steering torque signal) is used.
  • steering torque signal a signal proportional to the steering torque
  • position signals, steering angle signals or the like are appropriate.
  • suitable actual value sensors are to be used, the signals of which are compared in a differential amplifier circuit with the steering signals of the two signal paths.
  • the current of the electric motor with the help of a current sensor, for. B. a magnetic circuit with Hall generator measured.
  • output voltage is a function of the product of its control current and the current of the electric motor, the polarity of the output signal depends in ⁇ the direction of the motor current from.
  • the output signals are fed to the two operational amplifiers with the corresponding steering torque signals in a differential amplifier circuit.
  • the output signal of the current sensor is measured with the aid of two additional operational amplifiers connected in parallel
  • Differential amplifier circuit split into two paths by the output signal lines of the current sensor are connected to the inputs of one additional operational amplifier in any order and to the inputs of the other additional operational amplifier in the opposite order.
  • the outputs of the differential amplifiers are now assigned to the inputs of the first and second operational amplifiers in the manner that is customary in a setpoint / actual value comparison.
  • the difference between the steering signal and the current signal result in the controlled variable for controlling the electric motor. Since the current signal at the output of the Hall generator can be changed by means of the control current of the Hall generator, it is proposed in an embodiment of the invention to control the control current depending on a suitable parameter, for. B. the driving speed, etc. to change. Auxiliary support can thus be modified depending on the selected parameter.
  • a suitable parameter for. B. the driving speed, etc.
  • Auxiliary support can thus be modified depending on the selected parameter.
  • the power In power steering devices with power assist, it is common for the power to increase so much from a predeterminable point that the hand power on the steering wheel does not increase or only increases slightly. In one case, this is achieved by designing the current sensor so that its magnetic circuit saturates when the desired characteristic value is reached. As a result, the current signal no longer rises, so that the output signal of the first or second operational amplifier essentially rises from this operating point onwards
  • Steering torque signal is determined.
  • the same effect can be achieved by limiting the upper supply voltage of the additional operational amplifiers in accordance with the desired operating point.
  • the controller In principle, it is possible to design the controller with constant supply voltages for the additional operational amplifiers. According to an embodiment of the invention, however, it is proposed to keep the lower or upper supply voltage of the additional operational amplifiers variable and to modify them as a function of any parameters.
  • Such parameters can e.g. B. the vehicle speed or acceleration, the steering angle, etc.
  • FIG. 1 shows a diagram of the motor current over the input voltage as a function of the control current of the Hall generator for a specific upper and lower supply voltage of the additional operational amplifiers.
  • the steering device can only be operated with external power.
  • the positioning movements are effected exclusively by the electric motor and the signal transmitters for the steering signal or for the feedback actual value signal relate to travel ranges, positions, angular positions etc.
  • it can also be designed as a power steering device with assisted assistance. This acts as an actuating force parallel to the manual forces generated by the driver and the signal transmitters relate to steering torques, actuating forces, actuating torques or corresponding proportional variables, e.g. B. the current of the electric motor 1.
  • a power steering device usually consists of a steering wheel with a steering spindle, which is drivingly connected to the wheels of a vehicle via a steering gear and steering linkage. These parts are not shown.
  • an electric motor 1 on a suitable transmission member for. B. the steering shaft, the steering gear or the steering linkage.
  • a steering sensor here a steering torque sensor 3, generates opposite voltage potentials at its outputs 6 and 7 with a steering torque depending on the direction of rotation.
  • the output 6 is via a resistor 15 with a non-inverting input 9 of an operational amplifier 10 connected as a differential amplifier and via one Resistor 16 is connected to an inverting input 12 of an operational amplifier 13 connected in parallel as a differential amplifier.
  • the output 7 of the steering sensor 3 is present via a resistor 17 at an inverting input 8 of the operational amplifier 10 and via a resistor 18 at a non-inverting input 11 of the second operational amplifier 13.
  • the operational amplifiers 10 and 13 can be driven up to ground potential, so that the
  • Operational amplifier 10 only generates a signal at its output 20 if the voltage potential at output 6 of steering sensor 3 is greater than the voltage potential at output 7 of steering sensor 3. If this voltage signal is assigned to a left-turning steering torque, this steering signal for the left turn is only in one processed first signal path 5, to which the first
  • Operational amplifier 10 belongs. If the voltage state at the outputs 6 and 7 of the steering sensor 3 is reversed, so that the voltage potential at the output 6 is less than the voltage potential at the output 7, only the second operational amplifier 13 generates a signal at its output and thus forms a second signal path 4 for Steering signal, which can be assigned analogously to a right-turning steering torque or a right turn of the wheels.
  • the output signals of the operational amplifiers 10, 13 are positive and are supplied to two modulators connected in parallel via resistors 21, 22. These consist of comparators 23 and 24, which are generated in a known manner using a vibration generator 14
  • Resistors 34, 35 can be provided to stabilize the comparators 23, 24.
  • a current sensor in the example shown a magnetic circuit 75 with Hall generator 25, measures the current of the electric motor 1 and generates at its outputs 26, 27 a signal which is a function of the product of the motor current and the control current of the Hall generator.
  • the outputs 26, 27 are connected to the inputs 8, 9, 11, 12 of the first and second operational amplifiers 10 and 13 via resistors 28, 29, 30 and 31 in a differential amplifier arrangement in accordance with their assignment to a right or left turning steering torque of the electric motor 1 .
  • the influence of the assistant can be determined and depending on any operating parameters, for. B. affect speed, acceleration, steering angle, etc.
  • Limit auxiliary force or limit actuating force can be determined by designing the magnetic circuit 75 by going into saturation when the limit current is reached.
  • a potentiometer 43 is connected via resistors 36, 37 to the inverting inputs 8, 12 of the operational amplifiers 10, 13.
  • two additional operational amplifiers 50 and 51 with resistors 52 to 59 are connected as differential amplifiers between the Hall generator 25 and the operational amplifiers 10 and 13.
  • the output 27 of the Hall generator 25 is connected via the resistor 53 to the inverting input 60 of the operational amplifier 50 and via the resistor 58 to the non-inverting input 61 of the operational amplifier 51, while the output 26 of the Hall generator 25 via the resistor 54 to the non-inverting Input 62 of operational amplifier 50 and is connected via resistor 57 to inverting input 63 of operational amplifier 61.
  • Output 64 of operational amplifier 50 is through resistors 28 and 29 to the first and second Operational amplifiers 10 and 13 are connected, while the output 65 of the additional operational amplifier 51 is connected to the operational amplifiers 10 and 13 via the resistors 30 and 31.
  • the current signal similar to the steering signal, is divided into two signal paths 66 and 67 and the output signals of the additional ones
  • the output signals of the additional differential amplifiers are determined in the lower limit by the lower supply voltage and in the upper limit by the • - ⁇ upper supply voltage.
  • the lower limit value can be changed by a potentiometer 69 and the upper supply voltage by a potentiometer 68.
  • the output signal at outputs 19 and 20 is only determined by the magnification of the steering signal.
  • the output signal at outputs 64 and 65 is proportional to the product of the motor current and the control current Is of the Hall generator 25.
  • the control current - • the output signal depending on any parameters and thus the characteristic of the Force of the motor can be changed.
  • 3 shows characteristic curves of the motor current as a function of the control current, the Hall generator and the supply voltage.
  • the voltage range 68 characterizes the lower limit voltage, while the upper limit voltage determines the current value 69 above which the manual force no longer increases significantly.
  • the dashed curves show corresponding characteristic curves for changed control currents of the Hall generator.
  • the motor current is proportional to the motor torque and thus the actuating force that is available to adjust the wheels or to support the manual force.
  • the embodiment according to FIG. 4 largely corresponds to the embodiment according to FIG. 2, but with the difference that the output 6 of the steering sensor is connected to the ground potential, so that this serves as a reference potential. This simplifies the circuit structure with otherwise the same functionality.
  • FIG. 5 shows an embodiment of the invention similar to that of FIG. 2, but the supply voltages of the additional operational amplifiers 50 and 51 cannot be regulated. Instead, their outputs 64 and 65 are connected to a potentiometer 42 via resistors 40, 41 and diodes 74, 73. If the signal fed back from the outputs 64 and 65 exceeds the voltage value set at the potentiometer 42, the diodes 74, 73 limit the current feedback via the resistors 52, 56 to the inverting inputs 60, 63, which greatly increases the amplifier effect. As a result, the actuating force or the increases from this operating point
  • Auxiliary power assistance increases steeply depending on the steering signal.
  • Potentiometer 43 applies a variable bias voltage via resistors 36 and 37 to the inverting inputs of first and second operational amplifiers 13 and 10, so that outputs 19 and 20 only then turn on Signal arises when the steering signal is the set one
  • FIG. 6 shows a simplified embodiment similar to the embodiment according to FIG. 5.
  • the output 7 of the steering sensor 3 is connected to the ground potential in the embodiment according to FIG.
  • the resistors 53, 54, 55, 58 and 59 can be omitted, which increases the yield of the torque sensor.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Power Steering Mechanism (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)

Abstract

Un capteur de direction génère, selon le sens de direction, des signaux de direction positifs ou négatifs qui sont modifiés dans un système de commande, par une liaison logique d'éléments d'amplification avec des semiconducteurs pour se transformer en un signal de sortie pour le moteur électrique, adapté à une courbe caractéristique de valeur de consigne. Le moteur électrique exerce, selon la courbe caractéristique, des forces de réglage sur la colonne de direction d'un véhicule, lesquels, soit seuls, soit assistés par l'effort de direction manuel, déplacent les organes de direction. Pour chaque sens de direction est prévue une voie de signalisation séparée, les voies de signalisation présentant la même polarité. Il en résulte une commande simple et fiable des dispositifs de direction.
EP19900906206 1989-04-29 1990-04-24 Dispositif de direction assistee avec un moteur electrique Withdrawn EP0470115A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3914270 1989-04-29
DE3914270 1989-04-29

Publications (1)

Publication Number Publication Date
EP0470115A1 true EP0470115A1 (fr) 1992-02-12

Family

ID=6379795

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900906206 Withdrawn EP0470115A1 (fr) 1989-04-29 1990-04-24 Dispositif de direction assistee avec un moteur electrique

Country Status (3)

Country Link
EP (1) EP0470115A1 (fr)
JP (1) JPH04504695A (fr)
WO (1) WO1990013465A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2696252B1 (fr) * 1992-09-25 1994-10-28 Valeo Electronique Dispositif de contrôle d'une charge électrique et application à un dispositif de direction assistée de véhicule.
JPH06239249A (ja) * 1993-02-18 1994-08-30 Koyo Seiko Co Ltd 電動パワーステアリング装置
DE69523408T2 (de) * 1994-11-04 2002-06-20 Trw Inc., Lyndhurst Verfahren und Vorrichtung zur Steuerung eines Elektromotors

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6035664A (ja) * 1983-08-08 1985-02-23 Aisin Seiki Co Ltd 電動パワ−ステアリング装置
US4471278A (en) * 1983-09-14 1984-09-11 General Motors Corporation Bang-bang current regulator having extended range of regulation
JPS6181865A (ja) * 1984-08-16 1986-04-25 Honda Motor Co Ltd 電磁型倍力装置
US4624334A (en) * 1984-08-30 1986-11-25 Eaton Corporation Electric power assisted steering system
JPS62283067A (ja) * 1986-05-31 1987-12-08 Aisin Seiki Co Ltd 電動パワ−ステアリング装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9013465A1 *

Also Published As

Publication number Publication date
JPH04504695A (ja) 1992-08-20
WO1990013465A1 (fr) 1990-11-15

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